A thin film transistor liquid crystal display (TFT-LCD) is widely used in the field of image display for its advantages of high resolution, slim, compact, and low energy consumption, etc. However, because the TFT-LCD utilizes a maintenance driving pattern to control the passage and shutter of the light by the twist of liquid crystal molecules, this needs a reacting time, thereby resulting a longer response time of the TFT-LCD. As a result, when the TFT-LCD displays some images, especially a dynamic image, there exists a blurred edge or a blurred image. In light of this, how to improve the response time is the focus of the technology research for every firm.
An overdrive (OD) technology is an important technical method for improving the response time of the TFT-LCD, and it uses the relationship between the twisting speed of liquid crystal molecules and the driving voltage. The higher the driving voltage, the faster the twisting speed of the liquid crystal molecules is, and the faster the response time is. As shown in FIG. 1, when the prior art method is operated, input images are simultaneously delivered to an overdriving unit and a frame buffering device, and the overdriving unit determines the grey level of final output images via look-up tables based on the input images and images from the frame buffering device. At this time, the original resolution is maintained by images stored in the frame buffering device.
As the high resolution gradually becomes a current important developing aspect and trend of flat panel displays, the increase of the resolution will also greatly increase the amount of data needed to be processed, and the requirement of the frame buffering device will also greatly increase during a process of overdriving. Currently, the frame buffering device is usually equipped with a synchronous dynamic random access memory (SDRAM), and the price of the SDRAM is proportional to its capacity. As a result, if the resolution of input images increases, the required capacity of the SDRAM will also be increased, and thereby the amount of the SDRAM must accordingly be increased to match the expansion of the capacity. This will cause a significant increase of the manufacturing cost of TFT-LCD, and it disadvantages the cost control.